Each batch of 60 Starlink satellites will bring about a terabit of usable broadband capacity, according to SpaceX CEO Elon Musk. Credit: SpaceXWASHINGTON — SpaceX shared details about its largely secretive Starlink constellation program March 15, providing updated targets for commercial service, details about satellite design and the thought process behind why the company’s upper target is 12,000 satellites — about six times the number functioning in orbit for the rest of the world combined.SpaceX’s first launch with a large number of Starlink satellites was pushed back 24 hours, with a new launch window opening at 10:30 p.m. Eastern May 16. The Falcon 9 mission will carry 60 Starlink satellites. Though the spacecraft lack intersatellite links and other features expected in later iterations, SpaceX CEO Elon Musk said the satellites mark the start of deployment for a constellation designed to deliver internet access to unreached and underserved parts of the world. Musk, in a call with reporters, said SpaceX views 1,000 satellites as the point when Starlink becomes economically solid. “For the system to be economically viable, it’s really on the order of 1,000 satellites,” he said. “If we are putting a lot more satellites ...